#! /usr/bin/env python3


class Calc:
    """数学运算"""

    def __init__(self, a, b):
        """初始化"""
        self.a = a
        self.b = b

    def add(self):
        """实现加法计算"""
        pass

    def sub(self):
        return self.a - self.b
		

class Computer:
    """实现一个电脑类"""
    def __init__(self, name):
        """初始化"""
        self.__price = 5000
        self.name = name

    def show(self):
        """显示信息"""
        return self.__price
